Phosphonium salts and process for making same

ABSTRACT

Organo phosphonium salts of the formula:

United States Patent [151 3,689,60 1

Grayson et a1. Sept. 5, 1972 [54] PHOSPHONIUM SALTS AND PROCESS 2,651,656 9/1953 Ladd et a] ..260l970 FOR MAKING SAME Primary Examiner-Joseph Rebold [72] Inventors. Martin Grayson, Norwalk, Conn.

Patricia p y g Assistant Exarnrner-Anton SUttO Ridgefield Conn 06877 Attorney-William P. Splelman [73] Assignee: American Cyanamid Company, 57 ABSTRACT Stamford, Conn. Filed. Nov 17 1969 Organo phosphomum salts of the formula:

211 Appl. No.2 871,628 A l flz mQl Related U S Application D8 are prepared by reacting compounds of the formulas [63] Continuation Of Ser. N0. 674,107, 06:. 10, (I)

1967, abandoned, which is a continuation of Ser. No. 292,123, July 1, I963, abandoned. RlRzRsPCH CHiX (m with 11-0 wherein: X is halogen, Y is the residue of an [52] g d 'f ylating gfint, and Q is the residue of a reactant hav- 260/4851 260/488 R 260/561 1 260/5 66' mg elatmnegame 3MP Pmvidmg a 260/593 260/606 5 P 260/6065 260/968 ble hydrogen atom (H) WhlCh is replaced by the [51] Int. Cl b b 45/58 RR'RPCl-kCH-group of compounds 1 or 11 in forming the compound A. The phosphonium salts are use [58] Field of Search ..260/932, 968 ful as fire retardants in plastic&

[56] References Cited 7 Claims, No Drawilgs UNITED STATES PATENTS 2,535,175 12/1950 Tawney ..260/968X PHOSPHONIUM SALTS AND PROCESS FOR MAKING SAME This is a continuation of my copending application Ser. No. 674,l07, filed Oct 10, i967 now abandoned, which in turn was a continuation of application Ser. No. 292,123, filed July 1, 1963, now abandoned.

The present invention relates to organophosphorus compounds and to a method of preparing same. More particularly, the instant discovery concerns phosphonium salt derivatives of tertiary phosphines.

It has been found that tertiary phosphines generally will react with halo-substituted ethanol to produce the corresponding trialky-, tricycloalkyl-, or tri-aryl-Z- hydroxyethylphosphonium salts. In turn, these salts may be acylated using a lower alkonoic anhydride, lower alkanoic acid, or the like, to produce their corresponding trialkyl-, tricycloalkyl, or triarayl-2-acetoxyethylphosphonium salts.

The following equations illustrate this general reaction:

( e e mam xcmomon mnm PcmcmoH-x R, R, R each representing, as will be seen hereinafter, alkyl, cycloalkyl and aryl,

X representing halogen or tetraphenyl borate, and Y representing the residue of an acylating or esterifying agent. The following is a typical embodiment of generic equations (A) and (B), above;

The trialkyl-, tricycloalkyl-, and triaryl-Z-acetoxyethylphosphonium salts prepared as above may, in turn, be converted to their corresponding vinylphosphonium salts according to the following general equation:

a 9 base 9 9 mmmPcmcmoY-x n a=au on=ou x in which R, R, R", Y and X are the same as above.

The following is a typical embodiment of equation (C), above:

NMCO;

63 H (cm Pcmcmoccme 6 c Hm? CH=CH Cl tadecylphosphine, tn'hexadecylphosphine, dodecyldiethylphosphine, dioctylpropylphosphine, diethylbutylpho'sphine, butylethylhexylphosphine, tri(2-methoxypentyl)phosphine, tris-2-cyanoethylphosphine, diethyl-Z-ethoxyheptylphosphine, tricyclopropylphosphine, tricyclohexylphosphine, triphenylphosphine, diphenylnapthylphosphine, trixylylphosphine, tritolylphosphine, tris-(paraethoxyphynyl)phosphine, tris(para-chlorophenyl)phosphine, tris(2-chlorophenyl)phosphine, tn's(3-bromophenyl)phosphine, and the like.

Typical esterifying agents follow: lower alkanoic anhydrides, such as acetic anhydride, propionic anhydride, butanoic anhydn'de; lower alkanoic acids, such as formic acid, acetic acid, propionic acid, butanoic acid; acylating (C C alkanoyl) halides, such as acetyl chloride, propionyl bromide, butyryl iodide, octanoyl chloride, dodecanoyl bromide, stearyl chloride, hexanoyl bromide; isopropenyl acetate; aryl sulfonyl halides, such as para-toluenesulfonyl chloride, phenyl sulfonyl bromide, 2,4-dimethylphenylsulfonyl chloride; alkyl (lower) chloroformates, such as ethylchloroformate, butylchloroformate; alkyl (lower) carbonates, such as diethylcarbonate, dipropylcarbonate, dibutylcarbonate; ketene; dirnethyl sulfate; nitrosyl chloride; and trimethyl phosphate.

in equation (C), above, typical suitable inorganic and organic bases are: alkali inetal hydroxides, such as sodium hydroxide, potassium hydroxide, lithium hydroxide; alkali metal carbonates, such as sodium carbonate, potassium carbonate, lithium carbonate; alkaline earth meal hydroxides, such as magnesium hydroxide, barium hydroxide, calcium hydroxide; alkaline earth metal carbonates, such as magnesium carbonate, barium carbonate, calcium carbonate; activated alumina; and quaternary. ammonium hydroxides, such as tetraalkyl (lower)ammonium hydroxides, including tetramethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabenzyl-ammonium hydroxide; and basic ion exchange resins. (Typical are: polymeric quartemary ammonium salts, e.g., polymeric trimethylbenzyl ammonium chloride, etc.)

The reaction in equation (A) hereinabove is carried out at a temperature in the range of 30 to 250C, preferably 60 to 180C. The equation (8) reaction, above, is best carried out at a temperature in the range of 5 to C. As to equation (C), above, this reaction is generally carried out at a temperature in the range of 20 to C, preferably 50 to 150C.

Each of these three reactions may be carried out at atmospheric, sub-atmospheric or super-atmospheric pressure; preferably, however, reaction is carried out at atmospheric pressure. By the same token, the ratio of the reactants in each of equations (A), (B) and (C) is not critical, an excess of either reactant, in each equation, with respect to the other being suitable. In equation (B), however, an excess of about 10 percent by weight of the acylating agent relative to the phosphonium salt reactant is preferred. Generally in equations (A) and (C) stoichiometric amounts of the reactants are employed.

The reactions of equation (A), above, are best carried out in the presence of an inert organic solvent, i.e., a solvent which does not enter into or otherwise interfere with the reaction under the conditions contemplated herein. Typical solvents are dimethoxyethane, dioxane, ethylacetate, tetrahydrofuran, and the like.

The reactions of equation (B) similarly are best carried out in the presence of an inert organic solvent of the type described for equation (A), as well as acetic acid, dimethylformamide, diglyme, and the like.

As to equation (C), typical suitable inert organic solvents in which the phosphonium salt is solvent, which solvents do not interfere or enter into reaction to any substantial degree, are dirnethoxy-ethane, dioxane, dimethylfonnamide, diglyme, acetonitrile, ethylacetate, tetrahydrofuran, and other like linear and cyclic ethers, acetate esters (lower alkyl).

Alternatively, it has been found pursuant to the instant discovery that the products of equation (A), above, may be converted directly to the products of equation (C), thusly, (D)

in the presence of any base given above for equation (C) and at a temperature in the range of 100C. to 250C. As in equation (C), a solvent of the type given hereinabove for equation (C) is suitable and herein contemplated. if desired, the reaction may be carried out in the presence of a dehydrating agent, such as a siliceous agent including silica (e.g., silica gel), silicaalumina, and the like, in which other inert organic solvents are also suitable, e.g., aromatic hydrocarbons, such as toluene, benzene, xylene, cymene, and the like, methylene chloride, ethylene chloride, etc.

The products of equations (A), (B), (C), and (D) above are useful as fire retardants in plastics, e.g., from 0.5 to 30 parts by weight of any of above compounds when incorporated into 100 parts by weight of a thermoplastic polymer material, such as polyethylene, polypropylene, polystyrene, polyacrylate, polymethylmethacrylate, or the like, provides enhances fire retardance to the polymer material upon exposure to an open flame.

While the following examples specify certain details as to certain embodiments of the present invention, it is not intended that these details impose unnecessary limitations upon the scope of the instant discovery, excepting of course that these limitations appear in the appended claims:

EXAMPLE l Tri butyi-2-hydroxyethylphosphonium tetraphenylborate Tributyl-2-hydroxyethylphosphonium bromide, ob tained from combining tributylphosphine and Z-bromoethanol in l,2-dimethoxyethane and refluxing under nitrogen, is dissolved in water and treated with excess 0.1N sodium tetraphenylboron. The resulting precipitate is filtered and recrystailized from ethanol to yield product tributyl-Z-hydroxyethlphosphonium tetraphenylborate with melting point l24-l25C. Analysis of product (Found: C, 80.03; H, 9.00; P, 5.35.C;,@H.-,2O requires: C, 80.55; H, 9.25; P, 5.4770.)

As is evident from this example, the halide salts of Equation (A) may be converted, in situ or after recovery thereof, to the corresponding tetraphenylborate salts.

EXAMPLE n Tributyl-Z-acetoxyethylphosphonium bromide 1,2-dimethoxyethane (275 milliliters), freshly distilled from calcium hydride, Z-bromoethanol (133 grams, 1.06 moles), and tributylphosphine (204grams, 1.01 moles) are combined under nitrogen and refluxed at 85C. overnight with stirring. A heavy oil forms within an hour. lsopropenyl acetate (320 grams, 3.2 moles) and 48% HBr (3drops) are slowly added to the reaction mixture which is then refluxed 18 hours. Volatile components are removed in vacuo at C. Product (372.5 grams; 99.9 percent yield) remains as a thick hygroscopic oil, which could be forced to crystallize by stirring in a benzene-petroleum ether (boiling point 30-60C.) mixture. Crystalline tributyl-2- acetoxyethylphosphonium salt is obtained from part of the oily product by freeze drying a benzene solution of the oil.

EXAMPLE III Tributyl-Z-acetoxyethylphosphonium tetraphenylborate Tributyl -2-acetoxyethylphosphonium bromide oil (16.2 grams produced as in Example 11, above) is dissolved in water and treated with sodium tetraphenylboron (15 grams) dissolved in water. A white precipitate appears which is filtered and recrystallized from ethanol containing enough acetonitrile to cause solution at 5.24.boiling point of the mixture. Tributyl- 2-acetoxy-ethylphosphonium tetraphenylborate (16.7 grams) is obtained with melting point of 177179C. Analysis of product (Found: C, 76.65; H, 8.83; P, 5.24.

E H CEP requires: 8.94; P, 5.10%.)

EXAMPLE lV Triphenyl-2-acetoxyethylphosphonium iodide 2-iodoethyl acetate is prepared from the nucleophilic exchange reaction of sodium iodide and 2- chloroethylacetate in refluxing acetone under nitrogen (boiling point 8690C. at 33 milliliters mercury). Triphenylphosphine (7.35 grams) is reacted with 2- iodoethylacetate (24 grams) under nitrogen with stirring at C. for 4.5 hours. The excess 2- iodoethylacetate is distilled of in vacuo. Crude, brown crystalline product (14.20 grams) is obtained by washing oily residue with ether. It is washed with ether, ethylacetate, and acetone and recrystallized from acetonitrile to give product (7.90 grams) with melting point l6l163C. Analysis of product (Found: C, 55.16; H, 4.80; l, 26.77; P, 6.45.C,,H,,O,[P requires: C, 55.47; H, 4.66; l, 26.66; P, 6.51%.)

Example IV represents still another embodiment of the present invention wherein the product salts of Equation B, above, are prepared directly from the reaction of a 2-haloethyl acetate with a tertiary phosphine of the type contemplated herein.

The process of Example IV, above, may be carried out using any of the tertiary phosphine reactants contemplated herein and the corresponding tri-substituted -2-acetoxyethylphosphonium halide produced and recovered, according to the following equation wherein R, R',R, X, and V have the given hereinabove in equations (A) and (8).

Equation (E) is best carried out at a temperature in the range of 5 to 150C, preferably at the reflux temperature of the solvent employed. Typical inert organic solvents contemplated for equation (E) are acetone, lower alkanol (ethaml, lmtanol), plus the solvents listed heteinabove for equation (C). The reaction underequation(E),asshowninExamplelV,supra,is best carried out under inert conditions, such as under nitrogen. Other Z-haloethyl acetate reactants contemplated. are Z-bromoethyl acetate and Z-chloroethyl TABLE D 83 9 e R R'R'lE'CHaCHaOH base R R R P CH- CH2X Product of 1211- 600 ml.

Example ample Temp., Dehydrating of number number Base 0. agent solvent Product 1 VI NaiCO; 120 Silica gel DME... Vinyltrlbutylphosphonium chloride.

2. XI &(OH): 100 S11lca-alumlna'-. DME. Viuyltrldodeeylphosphonlum chloride.

3.. XII.. LhCO: 220 THF. Vlnyltrlheradecylphosphonlum chlorlde.

4 XV. LiOH 1B0 Slllca-alumina' Dionne- Vlnyldleth l-2-ethoxyethylphosphoulum chloride.

5. XVI Mg(0H)2 150 Silica gel DME... Vinyltrie cohoryl hos honium brornlde.

6.. XVIIL. NazCOi 250 Dloxans. VinyldirF enylnsp thy phosphonlumlodlde.

7. XIX. 131-100; 205 do wit henyl hosphonlum iodide.

8.. XX-.." NmOO: 200 DMEo, Vlnyltrl para-c orophen l)phosphon|um clilorlde.

9.. XXL." 175 DME... Vinyltrltpara-tolybphoep oulum chloride.

Activated alumina. Finely-divided eulstes. *191 F:PME=W risers-$ 2 Tfl firah s- -a TABLE E 0 Example g p-i No. R R'BJP+ XCHaG-IhO CH; C. Solvent Product 10 Tridodaoylphosphine X=Br Reflux" Ethanol..... "Irldodecyl-2-eoetoxvethylphosphonlum bromide. 11 Trlcyclohaxyl hos hine X=I 85 Acetonltrlle. Trio clohexyl-Z-ecetoxyethylphosphonlumiodide. 12 'Irls(2-chlorop any )-phosphine.... X=Cl Reflux Acetone.. Txglmdfl-leglorophanylhmtoxyethylphosphonlum 13 Tris(Z-methoxypentyl)-phosphlne X=I 60 Dioxane.... il-aoetoryethylphosphonlumlodldo.

By finely divided particulates in Table (D) is inin which R' and R" each represent lower alkyl and R tended 28 to 200 mesh. Larger or smaller particulates represents hydrogen or lower alkyl; secondary phosare likewise within the purview of the instant discovery. phines and phosphine oxides of the formula EXAMPLE LX 0 a R!!! Tributylvinylphosphonium bromide H 1/ 'lributyl-2-acetoxyethylphosphonium bromide (23.7 30

millimoles) is dissolved in 1,2-dimethoxyethane (25 milliliters) and sodium carbonate (5.0 grams, 47 milin which (a) is 0 or i and is the same as above; limoles) is added. The mixture is stirred at reflux under nitrogen for 8 hours. The solid is filtered ofi and washed with hot 1,2-dimethoxyethane. The combined fl filtrates are evaporated to leave a semi-solid residue. Recrystallization from ethyl acetate yields product 0a tributylvinylphosphonium bromide (3.3grams, 10.7

millimoles, 45 percent yield with melting point l48-l5 in which (a) is 0 or 1 and H! is lower alkyl or phenyl; 0C.). Further recrystallization from ethylacetateaceto-nitrile raises the melting point to l5l.5to H Pursuant to the present discovery, the products of Tables B, C, D, and E, above, may be reacted with reactants containing an electronegative group and an active hydrogen (Le, a readily replaceable hydrogen atom) to produce the corresponding organophosphorus derivatives. Typical such reactants naphthene; sammwd and unsaturawd substituted and are: esters of the formula: 50 unsubstituted cycloaliphatic ketone, such as 2,4- 2 dimethylcyclopentanone, 2,4-dimethylcyclopentene-l- H o R, one, isophorone, and the like; indene, nitroor hydroxy-substituted indene; fluorene, nitroor hydroxy-sub stituted fluorene, and other like reactants having an in which Z is hydrogen, alkyl C -C are cycloalkyl, and elecmmesafive group and an active hydrogen.

R" is lower alkyl; The product salts of this reaction have the following general formula 2! II('JN0 l ea 9 u m rt mrcmcmq X in which 2' is hydrogen or lower alkyl;

wherein R, R, R, and X have the meanings given 0 011 55 f E H hereinbefore and O is the residue of a reactant of the R C- -P type described just above, which reactants contain a ii OR" replaceable hydrogen which has been replaced and the residue is identified as Q, the active hydrogen having 6 9 been replaced by R R R PCH, CH,. For example: (orum l cmc me no 0.11.11

C 0 Calls 9 & I

1'; as a heavy yellow oil. This oil is converted to a crystal z line derivative, m l 37-l 39C., by treatment with a l J 9 N aqueous solution of sodium tetraphenyl boron.

I Analysis calculated for C I-I OJB: C, 78.12; H, 4 10 8.33; P, 4.20. Found: C,78.12; H, 8.79; P, 4.47.

The following examples further illustrate this reaction, Examples 1.x1v through LXXXVII of Table F EXAMPLE LXI being carried out essentially as in Example LX(a), infra, excepting, of course, as shown in Table F, 500 milliliters of solvent being used in each example:

6 9 EXAMPLE LX norm); 1' 011,0 Inca- 01mm s o e mHmPoHmmcH ocnmsr 001K! I Trihutylvinylphosphonium bromide (15.4 grams, 0.05 mole) is allowed to react with 50 milliliters of Tributylvinylphosphonium bromide (15.4 grams, ethyl acetoacetate and five drops of 10 percent sodium 0.05 moles) is allowed to react with 50 milliliters of hydroxide for 3 hours at 75C. Treatment of the reacdiethylmalonate and five drops of a 10 percent aqueous tion mixture with petroleum ether yields 90 percent of sodium hydroxide solution. The reaction mixture is the product as a heavy oil which can be converted to heated at l-l C. for 3 to 5 hours and then cooled the crystalline tetraphenyl borate (mp l63-l 65C. and treated with petroleum ether to precipitate the 30 Analysis calculated for C l-l OflBz C, 78.51; H, product 8.99; P, 4.61. Found: C, 77.8l; H, 8.93; P, 4.83.

a .ll: mofiom C L 8538 4 mozxfi ov 3 7 --5 =ui 3 BE JQMA n L Q 6 no How moz mo 1 3 Ema. a oafio h c4 HA 4953 m5 NQEQEAEGC 3 min 225 9 =4 22.5 3 E NA 5 0% 6 moiomcmofioiifiv o l; c2 .3585 301M c 830 3 A ENA EOflO O 6 25 0 8 .w w moEo m efifizfifiv 3M5: :56 9 w Eflovmowfio 05 0 R: 55 169? 3 o o o NNN 453 i uo wmoioiofl wmmoiom emo aozmoz fiofiowioiofiu o 2 .5585 mo z 3 o 2 HEEN BNQ N N 6 =mow oioiomz m oz mowmo o S 52. mo z i o 3 E53" ENq 5 Ewoofioiofiommoz moo mo e o S ain zoio 3 o 3 5M DNA 3 9 m 00 238 m 0 a E 2 2 2 m 650 5:03am 3 3 ofiaanw B32 33 3 32 3 55050 EEEE m h NAQQH 55 J 30 H m mofiomaov mm 0 i6 8 55 zmfiv .3 5 0 .2 E NDGG 6w. J m m mfiofiomzfiov e o 8 53 zofio 3 ni sfi s fiflwfixa 3 PS 5533 6 QQEE OQBV a no z bs: mo z .3 sfifi z 3 EM -5553 6 Eozvfi ovmoiofiomqoz fi hma imozm .3 15 962 3 NS AEA flo qovmmoiofiommfiz S -6 6 zzfidv .3 4552 3 MHMNM 503 m mzoovmofioiomama: 8 E5 zofio 3* 2520035 3 ES J53 w 69 o mQmum Nov fiaQoovmo 3 EE mozzfig .3 a 5g E503 iml fioddza SLHAESSQim=ovoioiom A AU BVH 3 ame moi .3 zEdSoEo EG 3 5 A JUGS J N oHe hzov mU mo monH zo-mnv Ill 8 mme EEfifiq 3 3 Bu U03 \o w n 0/ Q0 E0 04 o mofioiom mowfio M o 8 EQ mofi =4 0 0 Q EA JUS. 2 95 0a 233 5 a a 8 z 2 2 i diwn. 652cm 3 a 3.525 s: s: 8 636 "8 E EQ l w H 349 nmmoo/ Q HHUO/ mo-mo mom mo nmov mov EU & w \m mw-oo O O V I 3 E mmo z 6 H00 0 O c HEHW HTWMHMNNH w mQ mom -qov Om Q Om l cm MSQ I zfi mn ov 04 c N EN I banana 0 I 0.2 a Q -N Q 9 iU-NQN W02 $0 I am bw-NH. 0A |I|| 0A HQ krunmfl mo mU m SEUV 0 9 :0 L in .HSQ ZAROV c A 4 o d NN agq 5 -@31003&9o flw muma mo mov qmaz 2 Emma. mO Z o A QmdQOOvmUEuO e m A I HDNNNQ M6 0 mwU O 5 3550 .258 mm 20 O l 2 MSG 2050 c A NO 0 O o a MAN HNNNA nm. 0 I -m- D O/ e \ENHMOQQEOVA-NRZQN OV \mm Q00 I 3 HSQ 69: a 00 uA E ii QNNNQ H a m mu mum A-EOV mm D l S 2MB NQZ c A O a A EA EA fl v m 0 .E as m d U a 2 2 2 B i508 5:95am 3 8 0355 32 32 3 a uuzcucou H @549 wherein R, R and R each represent alkyl C C lower-alkoxy-substituted alkyl C -C cycloloweralkyl, phenyl, naphthyl, or substituted phenyl in which the substituents are lower alkyl, lower alkoxy or halogen;

X is halogen; and Qis in which R" and R" are lower alkyl and R"" is hydrogen or lower alkyl; and

\ III in which a is 0 or 1 and R is lower alkyl or phenyl.

2. A compound of claim 1 having the formula wherein R" and R'" each represent lower alkyl, R'" represents a member selected from the group consisting of hydrogen and lower alkyl, and R, R, R, and X are the same as in claim 1.

n 3. The compound 03H; 0 [win-norm)wtmn omomw moclntm cl e in, i :9 7w,

4. A compound of claim 1 having the formula RIM [mmavrcmcml' :l x

wherein a is a value from 0 or 1, inclusive, R' is a member selected from the group consisting of lower alltyl and phenyl, and R, R, R, and X are the same in claim 1.

5. The compound /0 CsHs [(Cfl-hXCrHIHCtHu) PCHsCHgP 1 01 0 Calls 6. The compound I OCH: [(CHOsI CHICH'L 7. A process for preparing a compound of the formula a a wrcmcmm x wherein R, R, and ll each represent alkyl C C lower alkoxy substituted alkyl C C cycloloweralkyl, phenyl, naphthyl, or substituted phenyl in which the substituents are lower alkyl, lower alkoxy or halogen;

X is halogen and Q is a radical defined below, said process comprising reacting a phosphonium salt having the formula with a reagent selected from the group consisting of beta-substituted ketones of the formula in which R" and R" each represent lower alkyl and R represents hydrogen or lower alkyl said selected reagent having an electronegative group causing a hydrogen atom of the reagent to be replaceable, the selected reagent being represented by the formula HQ wherein l-l represents said replaceable hydrogen atom and Q represents the radical that remains from the selected reagent after said hydrogen atom has been replaced. 

2. A compound of claim 1 having the formula wherein RV and RVI each represent lower alkyl, RVII represents a member selected from the group consisting of hydrogen and lower alkyl, and R1, R2, R3, and X are the same as in claim
 1. 3. The compound
 4. A compound of claim 1 having the formula wherein a is a value from 0 or 1, inclusive, R'''''' is a member selected from the group consisting of lower alkyl and phenyl, and R1, R2, R3, and X are the same in claim
 1. 5. The compound
 6. The compound
 7. A process for preparing a compound of the formula (R1R2R3PCH2CH2Q)+.X-wherein R1, R2, and R3 each represent alkyl C1-C16, lower alkoxy substituted alkyl C1-C16, cycloloweralkyl, phenyl, naphthyl, or substituted phenyl in which the substituents are lower alkyl, lower alkoxy or halogen; X is halogen and Q is a radical defined below, said process comprising reacting a phosphonium salt having the formula with a reagent selected from the group consisting of beta-substituted ketones of the formula in which RV and RVI each represent lower alkyl and RVII represents hydrogen or lower alkyl said selected reagent having an electronegative group causing a hydrogen atom of the reagent to be replaceable, the selected reagent being represented by the formula HQ wherein H represents said replaceable hydrogen atom and Q represents the radical that remains from the selected reagent after said hydrogen atom has been replaced. 